Apparatus and Method for Delivering a Biocompatible Material to a Surgical Site

ABSTRACT

A device for delivering a biocompatible material to a surgical site includes a cannula having proximal and distal portions and at least a first interior lumen disposed therebetween through which the biocompatible material is delivered. The device further includes an initiation member for initiating cross-linking of the biocompatible material while the biocompatible material is within the cannula. The cannula may include a heating element to thermally initiate cross-linking. Alternately, the cannula may include a second lumen for transmitting light from a light source. A movable blocking element controls the amount of light that passes into the first lumen. A method of delivering a curable biocompatible material to a surgical site includes positioning a distal portion of a cannula adjacent the surgical site and introducing the biocompatible material through a first lumen of the cannula. Cross-linking of the biocompatible material is then initiated while the biocompatible material is within the cannula.

FIELD OF THE INVENTION

An apparatus and method for surgical procedures, more particularly aminimally invasive apparatus and method for delivering a biocompatiblematerial to a surgical site during various orthopedic procedures.

BACKGROUND OF THE INVENTION

The musculoskeletal system is subject to injury caused by traumaticevents as well as by a number of diseases. Repair of connective tissueof the musculoskeletal system is commonly performed. By way of example,articular cartilage is a type of hyaline cartilage that lines thesurfaces of the opposing bones in a diarthrodial joint (e.g., knee, hip,shoulder, etc.). Its primary function is to permit smooth, nearfrictionless movement during articulation between bones of the joint byproviding a low-friction interface between the contacting cartilagesurfaces of the joint. Articular cartilage is also load bearing, andserves to transmit and distribute compressive joint loads to theunderlying subchondral bone.

Articular cartilage is typically damaged in one of two ways, acutetrauma suffered through physical activity (such as twisting motion ofthe leg, sharp lateral motion of the knee, or repetitive impact), ordegenerative conditions (such as arthritis or systemic conditions). Inaddition, as a person ages, articular cartilage loses mechanicalstrength, rendering the cartilage even more susceptible to trauma.Because articular cartilage tissue is aneural, i.e., having few or nonerves, and avascular, i.e., having few or no blood vessels, the healingof damaged cartilage is limited.

Consequently, various surgical methods are available for the treatmentof damaged tissue, such as cartilage. In one treatment approach, thedamaged tissue is removed and replaced with natural or syntheticmaterials that are physiologically acceptable to the human body andwhich perform the function formerly performed by the material removed.Recently, various orthopedic surgical procedures have replaced nativetissue, such as cartilage, with a curable biocompatible material. Suchsurgical procedures have been performed using minimally invasivetechniques, such as arthroscopic and endoscopic techniques, that allowas much of the healthy tissue as possible to remain. One type ofbiocompatible material that has shown promise for effecting soft tissuerepair is hydrogels. Hydrogels are particularly suitable for minimallyinvasive procedures because they provide controllable phase change, suchthat the hydrogel may be injected through the minimally invasive devicewhile in a liquid state and then cured in-situ to form a solid or a gel.

While the use of hydrogels has generally been successful to effect jointrepair, their use does have some drawbacks. One such drawback is thatwhile the hydrogel is in a liquid form, such as when delivering thehydrogel to a surgical site through the minimally invasive device, ithas a relatively low viscosity. Consequently, the hydrogel flows easilyand is therefore difficult to contain at the treatment site. Moreover,leakage of the hydrogel into or onto the tissue surrounding the surgicalsite may not be desirable in some surgical procedures. As a result, theuse of hydrogels to effect joint repair has been heretofore limited.

Therefore, there is a need for improvements in a method and apparatusfor delivering a biocompatible material to a surgical site.

SUMMARY OF THE INVENTION

Apparatus and method of delivering a biocompatible material to asurgical site that confines the biocompatible material to a desiredlocation at the surgical site. The apparatus and method may also reduceor prevent the leakage of the biocompatible material to the surroundingtissue.

In one embodiment, a device for delivering a curable biocompatiblematerial to a surgical site during a surgical procedure, such as aminimally invasive surgical procedure, includes an elongate cannulahaving a proximal portion adapted to be located outside a body duringthe surgical procedure and a distal portion adapted to be located withinthe body during the surgical procedure and positioned adjacent thesurgical site. The elongate cannula includes an outer wall that definesa first interior lumen disposed between the proximal and distal portionsand through which the biocompatible material is delivered. The devicefurther includes an initiation member for initiating cross-linking ofthe biocompatible material while the biocompatible material is withinthe cannula.

In another embodiment, the initiation member may include a resistiveheating element thermally coupled to the outer wall of the cannula. Theheating element is adapted to heat at least a portion of the outer wallto thermally initiate cross-linking of the biocompatible material. Insuch an embodiment, a temperature element may be coupled to the outerwall for measuring a temperature indicative of the temperature of thebiocompatible material. The temperature element may, for example, be athermocouple and be located adjacent the distal portion of the cannula.An outer surface of the outer wall may include an insulating layer toreduce heat transfer to surrounding body tissue when the cannula ispositioned within the body. The heating element and the temperatureelement may be operatively coupled to a controller for controlling theheating element in response to the temperature sensed by the temperatureelement. In this way, enhanced control of the curing process of thebiocompatible material may be achieved. In addition, at least a portionof the outer wall of the cannula may be formed of a material thatprovides visualization of the biocompatible material through the outerwall.

In another embodiment, the initiation member may include a light sourcecapable of photo initiating cross-linking of the biocompatible materialwhile in the cannula. In this embodiment, the cannula includes an outerwall and a first interior lumen disposed between the proximal and distalportions through which the biocompatible material is delivered to thesurgical site. The light source is external to the cannula and may becoupled to a light cannula having a distal portion adjacent the surgicalsite. Light is transmitted through the light cannula and out of thedistal portion. At least a portion of the outer wall is formed of amaterial capable of transmitting light therethrough and into the firstinterior lumen to photo initiate cross-linking of the biocompatiblematerial. The light source may be coupled to a controller forcontrolling the wave length, duration and/or intensity of the lighttransmitted into the first interior lumen. In this way, enhanced controlof the curing process of the biocompatible material may be achieved.Additionally at least a portion of the outer wall of the cannula may beformed of a material that provides visualization of the biocompatiblematerial through the outer wall.

In another embodiment, photo initiation may be used to initiatecross-linking of the biocompatible material while in the cannula. Thus,the initiation member may again include a light source. In thisembodiment, the cannula includes an outer wall and a first interiorlumen disposed between the proximal and distal portions through whichthe biocompatible material is delivered to the surgical site. A wall ofthe first lumen includes a first wall portion formed of a materialcapable of transmitting light therethrough. The cannula further includesa second interior lumen disposed adjacent the first interior lumen andadapted to transmit light within the second lumen from the light source.A wall of the second lumen includes a second wall portion formed of amaterial capable of transmitting light therethrough, wherein the firstand second wall portions are generally aligned so that light from thesecond interior lumen may pass through the first and second wallportions to photo initiate cross-linking of the biocompatible materialin the first interior lumen. The device may further include a blockingelement positioned in either the first or second interior lumen, theblocking element movable between a first position wherein light from thesecond interior lumen may pass through at least a part of the first andsecond wall portions and into the first interior lumen, and a secondposition wherein less light may pass through at least one of the firstand second wall portions than in the first position. The device mayinclude a controller operatively coupled to the blocking element to movethe blocking element between the first and second positions to therebycontrol the amount of light transmitted into the first interior lumen.In this way, enhanced control of the curing process of the biocompatiblematerial may be achieved. Additionally, the cannula may include a systemfor visualizing the surgical site.

A method of delivering a curable biocompatible material to a surgicalsite in the body includes positioning a distal portion of a cannulaadjacent the surgical site and introducing the biocompatible materialthrough a first interior lumen of the cannula. Cross-linking of thebiocompatible material is then initiated while the biocompatiblematerial is within the cannula and prior to its delivery to the surgicalsite. In one embodiment, cross-linking is initiated by heating at leasta portion of the cannula. The method may further include monitoring atemperature indicative of the temperature of the biocompatible materialand varying heat provided to the portion of the cannula based on thetemperature. In another embodiment, cross-linking is initiated bytransmitting light through a portion of the outer wall of the cannulaand into the first interior lumen to photo initiate cross-linking. Inanother embodiment, cross-linking is initiated by transmitting lightthrough a second interior lumen of the cannula and transmitting thelight from the second interior lumen to the first interior lumen tophoto initiate cross-linking of the biocompatible material. The methodmay further include moving a blocking element between first and secondpositions to control the amount of light transmitted from the secondinterior lumen to the first interior lumen.

These and other embodiments will become more readily apparent to thoseof ordinary skill in the art upon review of the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrates embodiments of the inventionand, together with a general description of the invention given above,and the detailed description given below, serves to explain theinvention.

FIG. 1 is a cross-sectional view of an apparatus for delivering acurable biocompatible material to a surgical site in accordance with oneembodiment;

FIG. 2 is a cross-sectional view of an apparatus for delivering acurable biocompatible material to a surgical site in accordance withanother embodiment; and

FIG. 3 is a cross-sectional view of an apparatus for delivering acurable biocompatible material to a surgical site in accordance withanother embodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, one embodiment of a device 10 for delivering acurable biocompatible material 12 to a surgical site 14 is schematicallyillustrated. The device 10 may be used in various surgical procedures,including orthopedic surgical procedures to effect repair of themusculoskeletal system. In one embodiment, the device 10 may be used inminimally invasive procedures, such as arthroscopic and endoscopicprocedures, to effect repair of a joint. In one embodiment, the device10 may be used in orthopedic surgical procedures in general or to repairthe cartilage within a diarthrodial joint, such as the knee. By way ofexample, as shown in FIG. 1, the surgical site 14 may include bone 15,subchondral bone 15 a, and cartilage 15 b wherein cartilage 15 bincludes a defect 15 c that is to be repaired using embodiments of theinvention. The invention, however, is not so limited, as those ofordinary skill in the art will recognize a wide range of surgicalapplications that may benefit from embodiments of the inventiondescribed herein. Thus, embodiments of the invention are not to belimited to orthopedic surgical procedures in general, or to the repairof cartilage in diarthrodial joints in specific.

The device 10 includes an elongate cannula 16 having a proximal portion18 located outside the body of a patient during a surgical procedure,and a distal portion 20 located within the body of the patient andpositioned adjacent the surgical site 14. The device 10 includes anouter wall 22 that defines a first interior lumen 24 disposed betweenthe proximal and distal portions 18, 20 through which the biocompatiblematerial 12 is delivered. The device 10 may include a supply orreservoir 26 of curable biocompatible material in fluid communicationwith the proximal portion 18 of the cannula 16 to supply the firstinterior lumen 24 with the biocompatible material 12. As shown in FIG.1, the end of the cannula may include an elastic seal 27 to reduce orprevent tissue damage as the device 10 is inserted into the body andtoward the surgical site 14. In addition, seal 27 may facilitate sealingof the distal portion 20 of cannula 16 with the tissue at the surgicalsite 14. For example, the tissue surrounding defect 15 c may not besmooth but may be rough or irregular. In these applications, the seal 27may allow the distal portion 20 of the cannula 16 to conform to theirregular contour of the tissue to promote sealing and thus preventingor reducing the leakage of the biocompatible material 12 outside thetarget area. Moreover, although the distal portion 20 of the cannula 16is shown as generally straight, the distal portion 20 may have differentshapes depending on the application. For example, the distal portion 20may be semi-circular or otherwise curved to facilitate penetration ofthe cannula 16 through body tissue and within a joint (not shown).

For minimally invasive procedures, controllable phase change of thebiocompatible material may facilitate the delivery of the biocompatiblematerial 12 to the surgical site 14. In particular, in one embodiment,the biocompatible material 12 may be delivered through a portion of thedevice 10 while in a substantially liquid state and then partially curedwithin the device prior to delivery of the biocompatible material 12 tothe surgical site 14. The controllable phase change of the biocompatiblematerial allows that material to flow through a portion or substantialpart of the first interior lumen 24 of the cannula 16 while in a liquidstate, but yet be delivered to the surgical site 14 at least partiallycured. This may obviate the need for more invasive surgical techniquesthat may typically be used for locating the biocompatible material 12 atthe surgical site 14.

A hydrogel is one such biocompatible material 12 that can exhibit suchphase change properties and which may be used in the invention. Curedhydrogels may exhibit physical/chemical characteristics analogous tothose of human soft tissue, such as cartilage, and can demonstrate acombination of such properties as load bearing, shear stress resistance,impact absorption, and/or wear characteristics. The term hydrogelincludes liquid and/or semi-solid long chain hydrophilic molecules thatform cavities or spaces that contain entrapped liquids, typically water,at a concentration ranging from about 20% to about 95%. The cavitiesabsorb water (or other liquids) from the surrounding environment, andcan slowly release the water as the molecules biodegrade or experiencelocalized changes in load bearing.

Hydrogels may be classified according to composition (homopolymer,copolymer, multipolymer, or interpenetrating hydrogels), ionic charge(neutral, anionic, cationic, or ampholytic hydrogels), and/or structure(amorphous, semicrystalline, or hydrogen-bonded hydrogels). Methods,components, concentrations, conditions, etc. to produce hydrogels areknown by one skilled in the art such as described in U.S. Pat. Nos.6,949,590; 6,511,650; 6,497,902; Published U.S. Patent Application No.20060252159; and Hoffman (Advanced Drug Delivery Reviews, Vol. 43, 2002,pp 3-12) each of which are incorporated herein by reference in itsentirety.

Hydrogels may be prepared from natural polymers that include, but arenot limited to, collagen, hyaluronate, chitosan, gelatin, algenate,pectin, carrageenen, chondroiten sulfate, dextran sulfate, polylysine,carboxymethyl chitin, fibrin, dextran, agarose, and pullulan. Hydrogelsalso may be prepared from synthetic polymers that include, but are notlimited to, poly(2-hydroxyethylmethacrylate (HEMA), polyphazene,poly(ethylene oxide) PEO and its copolymers, polyesters such as PEG(polyethylene glycol)-PLA (polylactic acid)-PEG, PEG-PLGA-PEG, PEG-PCL(polycaprolactone)-PEG, PLA-PEG-PLA, PHB (poly(3-hydroxybutyrate)),P(PF-co-EG) plus or minus acrylate end groups, P(PER/PBO terephthalate),other polymers such as PEG-bis-PLA-acrylate), PEG-g-P(Aam-co-Vamine),PAAm, P(NIPAAm-co-Aac), P(NIPAAm-co-EMA), PVAc/PVA, PNVP,P(MMA-co-HEMA), P(AN-co-allyl sulfonate),P(biscarboxy-phenoxy-phosphazine), P(GEMA-sulfate). Hydrogels may beprepared from both natural and synthetic polymers, examples of whichinclude, but are not limited to, P(PEG-co-peptides),alginate-g-(PEO-PPO-PEO), P(PLGA-co-serine), collagen-acrylate,alginate-acrylate, P(HPMA-g-peptide), P(hema/Matrigel®), andHA-g-NIPAAm.

Hydrogels may be prepared from branched deoxyribonucleic acid (DNA) thatself-forms into various shapes (e.g., a cross, a “Y”, a “T”). These mayhave non-base paired termini to which a complementary sequence mayanneal (i.e., “sticky ends”). These may be used with ligases to link DNAstrands to each (e.g., Steele, B. Sep. 28, 2006, Cornell CHRONICLE, page7). Cross-shaped branched DNA forms a gel by linking into sheets of tinysquares that tangle in three dimensions; Y shapes form hexagonalstructures like a chain link fence that combine into a fibrousthree-dimensional form; T shapes create random, disorganized patternsthat resemble scales, etc. Properties such as rigidity and/or absorbanceof the resulting hydrogels may be altered by adjusting the types ofbranched DNA used and the DNA concentration.

In one embodiment, hydrogels are long-chain molecules cross-linked toone another. In another embodiment, hydrogels are long-chain moleculesthat are not cross-linked; while these are able to absorb liquids withintheir cavities, they are not soluble due to the presence of hydrophobicand hydrophilic regions in their structure. The term hydrogel is alsoapplied to hydrophilic polymers in a dry state (xerogel).

Cross-linking may be effected by physical, chemical, and/or photocross-linking. Physical cross-linking occurs due to ionic linkages,hydrogen bonding, van der Waals forces, or other physical forces.Chemical cross-linking occurs due to formation of covalent linkagesusing chemical initiators. Photo cross-linking, also termedphotopolymerization, of hydrogels may occur by exposure to ultravioletand/or visible light, either in the presence or absence of a photoinitiator. Examples of polymers and methods of use are described in U.S.Pat. Nos. 5,567,435 and 6,156,478; and Published U.S. Patent ApplicationNo. 20060252159. Examples of polymers/monomers suitable to formionically cross-linked hydrogels with adjustable gellation times aredisclosed in U.S. Pat. No. 6,497,902. Examples of polymers suitable toform porous hydrogels are disclosed in U.S. Pat. No. 6,511,650. Examplesof polymers suitable to form bioabsorbable polymer hydrogels forsustained release of drugs are disclosed in Published U.S. PatentApplication No. 2006/0251719.

Hydrogels may contain both hydrophobic and hydrophilic components.Preparation of these hydrogels does not rely on use of copolymers orphysical blending, but instead relies on hydrophobic and hydrophiliccomponents. These components are convertible into a one phasecross-linked polymer network structure by free radical polymerization,as described in U.S. Patent Application Publication No. U.S.2002/0161169.

Hydrogels may be formulated as temperature sensitive compounds,described in U.S. Patent Application Publication No. U.S. 2006/0188583.Polymers, either commercially available or synthesized, are dissolved inwater or other liquid, and an agent that facilitates cross-linking suchas sodium hyaluronate (SH) is added. The temperature sensitive hydrogelare liquid at about ambient room temperature (about 20° C.) andtransition to become a solid (gel) at about body temperature (about 37°C.). Any polymers may be used to prepare temperature sensitive hydrogelsas long as it possess the necessary properties to support the hydrogel.Examples of such polymers include, but are not limited to, N-isopropylacrylamide polymer, ethylhydroxyethylcellulose and its derivatives,poly(ethylene glycol)/poly(D,L-lactic acid-co-glycolic acid) blockco-polymers and analogs, and poly(etheylene oxide-b-propyleneoxide-b-ethylene oxide) (Poloxamers or PLURONICS® polymers, which areblock copolymers of the type ABA, consisting of a central, hydrophobicblock of polypropylene oxide, which is edged by two hydrophilic blocksof polyethylene oxide. The polymers are derived from the sequentialpolymerization of propylene oxide and ethylene oxide).

Hydrogels may be polymerized in-situ. U.S. Published Patent ApplicationNo. 2006/018894 describes in-situ polymerization of a hydrogel using UVlight in the presence of stratum corneum tissue. U.S. Published PatentApplication No. 2004/0241203 describes a fluid composition comprisingparticulate material, and a cross-linking agent, the particlescross-linking to form a matrix on introduction to the cross-linkingagent in or on a target tissue. Changing the amount of monomer andcross-linker can change the thickness and pore size of hydrogel layersas described in PCT application WO 00/66265.

Hydrogels may serve as an extracellular matrix (ECM), or bioscaffold, toprovide a surface upon which cells can attach. This may haveapplications in tissue engineering implantation. As one example,Schmedlen et al (Biomaterials 23 (2002) 4325) describe polyvinyl alcoholhydrogels that can be modified with cell adhesion peptides. As anotherexample, Khademhosseini et al. describe gradient hydrogels embedded withthe peptide Arg-Gly-Asp (RGD) that can bind cell integrins (membranebound receptors). Published U.S. Patent Application No. 2006/0233850discloses bioscaffolds formed of hydrogels that are cross-linked in-situin an infracted region of the heart.

Hydrogels may serve as drug delivery devices. In one embodiment, ahydrogel may gradually dispense a drug or other liquid within itscavities (e.g., U.S. Patent Application Publication No. 2006/0251719discloses a sustained-release, bioabsorbable polymer hydrogel drugpreparation). Such hydrogels form a complex with the drug throughphysiochemical interactions to effect sustained drug release, in effectforming a microcapsule. Techniques for preparing, loading, etc. suchhydrogels are known to one skilled in the art.

The invention, however, is not limited to hydrogels, as those ofordinary skill in the art will recognize other suitable biocompatiblematerials capable of being delivered to the surgical site by means of acannula, and cured to form a replacement material during a surgicalprocedure.

As noted above, however, the biocompatible material 12, such as ahydrogel, may exhibit a relatively low viscosity when in the liquidstate. The biocompatible material 12 then flows easily and thus passesthrough the cannula 16 with reduced resistance to flow and with arelatively small pressure gradient. While this may be desirable tofacilitate delivery of the biocompatible material 12 through the device10, the relatively low viscosity may make confining the biocompatiblematerial 12 to a desired target area of the surgical site 14challenging. In other words, the enhanced flowability of thebiocompatible material 12 may allow the material to essentially leakinto or onto the tissue surrounding the surgical site 14 or other areaswhere no biocompatible material is desired. Consequently, measures maybe taken to confine the biocompatible material 12 at a desired targetarea of the surgical site 14. For example, commonly assigned U.S.application Ser. No. 11/613,319, filed on Dec. 20, 2006, titled“Apparatus for Deliverying a Biocompatible Material to a Surgical Siteand Method of Using the Same,” discloses using an expandable confinementmember at the distal portion of the cannula to confine the biocompatiblematerial to the desired target area of the surgical site. Embodiments ofthe invention disclosed herein provide an alternate approach topreventing the biocompatible material from leaking into or onto thesurrounding tissue at the surgical site.

To address the flowability of the biocompatible material 12 at thesurgical site 14, the device 10 may further include an initiation member28 for initiating cross-linking of the biocompatible material 12 whilethe biocompatible material 12 is within the device 10. Initiatingcross-linking of the biocompatible material 12 initiates curing andresults in an increase in the viscosity of the biocompatible material 12so that the flowability of the biocompatible material 12 is reducedprior to its delivery to the surgical site 14. As illustrated in FIG. 1,in one embodiment the initiation member 28 may be configured as aheating element 30 for thermally initiating cross-linking of thebiocompatible material 12 within cannula 16. For example, the heatingelement 30 may be a resistive heating wire or coil, as is known in theart. In one embodiment, the heating element 30 is thermally coupled tothe outer wall 22 of the cannula 16 for heating at least a portion ofthe outer wall 22. The biocompatible material 12 may be in directcontact with the heated portion of the outer wall 22 or at least isthermally coupled to the outer wall 22, such as by high thermalconductivity materials (not shown), so that heat from the heatingelement 30 is transferred to the biocompatible material 12 to causethermal initiation of the biocompatible material 12. The heating element30 may be appropriately located along the cannula 16 such that theviscosity of the biocompatible material 12 is generally in a desiredrange when the biocompatible material 12 reaches the end of the cannula16 and is delivered to the surgical site 14. The viscosity range may beselected so as to retain the partially cured biocompatible material 12within the desired target area of the surgical site 14. Once deliveredto the surgical site 14, the curing process is completed in-situ to forma solid or gelled implant.

The viscosity of the biocompatible material 12 adjacent the end of thecannula 16 depends on several factors, including not only the locationof the heating element 30 along the cannula 16 but also the amount ofheating of the biocompatible material 12 by the heating element 30. Toprovide enhanced control of the curing process of the biocompatiblematerial 12, device 10 may include a controller 32 operatively coupledto the heating element 30 and capable of controlling the amount of heatgenerated by heating element 30 (i.e., the amount and/or duration ofheating). Device 10 may further include a temperature element 34thermally coupled to the outer wall 22 and adapted to measure atemperature indicative of the temperature of the biocompatible material12 in first interior lumen 24. For example, the temperature element 34may be located adjacent the distal portion 20 of the cannula 16 so as toindicate the temperature of the biocompatible material 12 adjacent theend of the cannula 16. The temperature element 34 may, for example, be athermocouple, thermistor, or other temperature sensing device known tothose of ordinary skill in the art. The temperature element 34 is alsooperatively coupled to controller 32 so as to control heating element 30in response to the temperature sensed by the temperature element 34. Inthis way, the curing process of the biocompatible material 12 may becontrolled so as to deliver the biocompatible material 12 to thesurgical site 14 at a viscosity sufficient to reduce or eliminateleakage of the biocompatible material 12 into or onto the tissuesurrounding the surgical site 14. Moreover, the controller 32 may alsobe operatively coupled to the reservoir 26 so as to supply thebiocompatible material 12 to the first interior lumen 24 at apredetermined rate or volume, which also factors in determining theviscosity of the biocompatible material 12 at the end of the cannula 16.For example, the controller 32 may supply biocompatible material 12 tofirst interior lumen 24 at a linear rate of about 1 μm/sec to about 10cm/sec or a volumetric flow rate of about 0.1 μl/sec to about 1.0ml/sec.

Because this embodiment uses thermal initiation to cross-link thebiocompatible material 12, it may be desirable to reduce the effects ofheating from heating element 30 on the surrounding body tissue. To thisend, the device 10 may include an insulating coating or layer 36 on theouter surface 38 of the outer wall 22 of cannula 16 at least along aportion thereof. In particular, the insulating coating 36 is locatedadjacent the heating element 30. Insulating layer 36 not only reducesthe heat transfer to the surrounding body tissue when the cannula 16 ispositioned within the body, but layer 36 also focuses the thermal energyfrom the heating element 30 to the biocompatible material 12, thusenhancing the thermally initiated cross-linking of the biocompatiblematerial 12.

In another embodiment, the device 10 may include a second cannula 40inserted into the body of the patient such that its distal portion 42 ispositioned adjacent the surgical site 14. The second cannula 40 carriesoptical instrumentation as is known in the art for viewing thebiocompatible material 12 within the cannula 16. To this end, at least aportion 44 of the outer wall 22 is formed of a material that providesfor visualization of the biocompatible material 12 through the outerwall 22.

FIG. 2, in which like reference numerals refer to like features in FIG.1, illustrates another embodiment of a device 50 for delivering acurable biocompatible material 12 to a surgical site 14. The device 50includes an elongate cannula 16 having a proximal portion 18 locatedoutside the body of a patient during a surgical procedure, and a distalportion 20 located within the body of the patient and positionedadjacent the surgical site 14. The device 50 includes an outer wall 22that defines a first interior lumen 24 disposed between the proximal anddistal portions 18, 20 through which the biocompatible material 12 isdelivered. The device 50 may include a supply or reservoir 26 of curablebiocompatible material in fluid communication with the proximal portion18 of the cannula 16 to supply the first interior lumen 24 with thebiocompatible material 12.

In this embodiment, initiation of cross-linking of the biocompatiblematerial 12 is achieved through photo initiation. Thus, the initiationmember 28 may be configured as a light source 52 for generating lightsufficient to photo initiate cross-linking of the biocompatible material12. To this end, device 50 may include a light cannula 54 that isinserted into the body of the patient such that its distal portion 56 ispositioned adjacent the surgical site 14. The light cannula 54 iscoupled to light source 52 and is capable of transmitting light out ofthe distal portion 56 of cannula 54. In one embodiment, the light source52 may be a fiber optic bundle positioned within light cannula 54 andadjacent distal portion 56. Alternately, the light source 52 may bepositioned away from the distal portion 56 of the cannula 54 and lightchanneled through the cannula 54 so as to be transmitted from the end ofthe cannula 54. Those of ordinary skill in the art will recognize otherlight sources that may be used in embodiments of the invention.Moreover, at least a portion 58 of the outer wall 22 of cannula 16 isformed of a material capable of transmitting light therethrough. Thus,light from light cannula 54 passes through the portion 58 of outer wall22 and into first interior lumen 24 to photo initiate cross-linking ofthe biocompatible material 12. Although only one light cannula is shownin FIG. 2, device 50 may include multiple light cannulas, which may, forexample, be circumferentially spaced about the periphery of cannula 16so as to transmit light into first interior lumen 24. The use ofmultiple light cannulas may provide a more homogeneous polymerization ofthe biocompatible material 12 in first interior lumen 24.

The viscosity of the biocompatible material 12 adjacent the end of thecannula 16 depends on several factors, including the wave length,duration and/or intensity of the light from light source 52, as well asthe size and location of the portion 58 of the outer wall 22 throughwhich the light is transmitted. These parameters may be varied tocontrol the curing process of the biocompatible material 12 within thecannula 16. In one embodiment, the light source 52 may be operativelycoupled to a controller 60 for controlling the light generated by thelight source 52. In addition, the portion 58 of the outer wall 22through which the light passes may be positioned along the cannula 16and sized such that the viscosity of the biocompatible material 12 isgenerally in a desired range when the biocompatible material 12 reachesthe end of the cannula 16. For example, the portion 58 may have a lengthfrom about 1 mm to about 10 cm. In this way, the curing process may becontrolled to deliver the biocompatible material 12 to the surgical site14 at a viscosity sufficient to reduce or eliminate leakage of thebiocompatible material 12 into or onto the tissue surrounding thesurgical site 14.

The controller 60 may also be operatively coupled to the reservoir 26 tosupply the biocompatible material 12 to the first interior lumen 24 at apredetermined rate or volume, which also factors in determining theviscosity of the biocompatible material 12 at the end of the cannula 16.For example, the controller 60 may supply biocompatible material 12 tofirst interior lumen 24 at a linear rate of about 1 μm/sec to about 10cm/sec or a volumetric flow rate of about 0.1 μl/sec to about 1.0ml/sec. The biocompatible material 12 may be configured such thatvisible light and/or ultraviolet light initiates cross-linking.Accordingly, the light source 52 may be configured to generate visibleand/or ultraviolet light as required by the specific application orcross-linking system. This embodiment may also include a second cannula40 for viewing the biocompatible material 12 within the cannula 16.Accordingly, at least a portion 44 of the outer wall 22 is formed of amaterial that provides for visualization of the biocompatible material12 through the outer wall 22.

FIG. 3, in which like reference numerals refer to like features in FIG.1, illustrates another embodiment of a device 70 for delivering acurable biocompatible material 12 to a surgical site 14. The device 70includes an elongate cannula 16 having a proximal portion 18 locatedoutside the body of a patient during a surgical procedure, and a distalportion 20 located within the body of the patient and adjacent thesurgical site 14. The device 70 includes an outer wall 22 and a firstinterior lumen 24 disposed between the proximal and distal portions 18,20 through which the biocompatible material 12 is delivered. The device70 may include a supply or reservoir 26 of curable biocompatiblematerial in fluid communication with the proximal portion 18 of thecannula 16 to supply the first interior lumen 24 with the biocompatiblematerial 12. The first interior lumen 24 is defined by a wall 72 havinga first wall portion 74 formed of a material capable of transmittinglight therethrough. In one embodiment, the first wall portion 74 isalong a distal portion 76 of wall 72 that forms first interior lumen 24.

The device 70 further includes a second interior lumen 78 disposedbetween the proximal and distal ends 18, 20 of cannula 16 and is adaptedto transmit light therethrough from a light source 80 operativelycoupled to second interior lumen 78. The second interior lumen 78 isdefined by a wall 82 having a second wall portion 84 formed of amaterial capable of transmitting light therethrough. The first andsecond wall portions 74, 84 are generally aligned with each other sothat light from second interior lumen 78 may pass through the first andsecond wall portions 74, 84 and into the first interior lumen 24 tophoto initiate cross-linking of the biocompatible material 12 containedtherein. In one embodiment, the light source 80 may be a fiber opticbundle positioned within the second lumen 78 such that the light source80 is adjacent the second wall portion 84. Alternately, the light source80 may be positioned away from the second wall portion 84 and the lightchanneled through the second interior lumen 84 and into the firstinterior lumen 24 via the first and second wall portions 74, 84. In oneembodiment, the first and second wall portions 74, 84 are substantiallyequal in length. The wall portions 74, 84 may be between about 1 mm toabout 10 cm. The biocompatible material 12 may be configured such thatvisible and/or ultraviolet light initiates cross-linking. Accordingly,the light source 80 may be configured to generate visible and/orultraviolet light as required by the specific application orcross-linking system. As shown in FIG. 3, the device 70 may includemultiple lumens (two shown) for introducing light into the firstinterior lumen 24, as dictated by the specific application. Furthermore,in this embodiment, the outer wall 22 may be formed from an opaque orother material to protect body tissue from light exposure.

To provide control of the curing process of the biocompatible material12, the device 70 may further include a blocking element 86 in eitherthe first or second interior lumens 24, 78. The blocking element 86 isadapted to control the amount of light from the second interior lumen 78that passes through the first or second wall portions 74, 84 and intothe first interior lumen 24. For example, as shown in FIG. 3, the firstinterior lumen 24 may include the blocking element 86. Alternately, thesecond interior lumen 78 may include the blocking element 86 (notshown). In any embodiment, the blocking element 86 is movable between afirst position wherein light from the second interior lumen 78 passesthrough at least a part of the first and second wall portions 74, 84 andinto the first interior lumen 24, and a second position wherein lesslight passes through at least a portion of the first and second wallportions 74, 84 and into the first interior lumen 24. For example, theblocking element 86 may have a position that exposes the entire firstand second wall portions 74, 84. The blocking element 86 may also have aposition that completely closes off the first and second wall portions74, 84 and prevents any light to pass therethrough. Additionally, theblocking element 86 may include a position that partially closes off thesecond wall portion 84, as shown in FIG. 3. The movement of the blockingelement 86 between the first and second positions controls the amount oflight that passes into the first interior lumen 24 and thereforeprovides some control of the curing process of the biocompatiblematerial 12 within first interior lumen 24.

In one embodiment, the device 70 includes a controller 88 that isoperatively coupled to the blocking element 86 for moving the blockingelement 86 between the first and second positions. The controller 88 mayalso be operatively coupled to the light source 80 to control the wavelength, duration and/or intensity of the light generated by light source80. In this way, the light source 80 and blocking element 86 may becontrolled such that the viscosity of the biocompatible material 12 isgenerally in a desired range when the biocompatible material 12 reachesthe end of the cannula 16 and is delivered to the surgical site 14. Thecontroller 88 may also be operatively coupled to the reservoir 26 so asto supply the biocompatible material 12 to the first interior lumen 24at a predetermined rate or volume, which also factors in determining theviscosity of the biocompatible material 12 at the end of the cannula 16.For example, the controller 88 may supply biocompatible material 12 tofirst interior lumen 24 at a linear rate of about 1 μm/sec to about 10cm/sec or a volumetric flow rate of about 0.1 μl/sec to about 1.0ml/sec.

In another embodiment, the device 70 further includes a visualizationsystem for viewing the surgical site 14. In such an embodiment, device70 may include a cannula 90 carried within cannula 16 having a distalportion 92 positioned adjacent the surgical site 14. The cannula 90carries optical instrumentation for viewing the surgical site 14, as isgenerally known in the art. As recognized by those of ordinary skill inthe art, the cannula 90 may alternately be positioned external to thecannula 16 for viewing the surgical site 14, such as that shown in FIGS.1 and 2.

In use, after the surgical site 14 has been prepared, such as byaspiration of fluid at the surgical site 14 and/or contouring theunderlying tissue as dictated by the specific application, the cannula16 is inserted into the body of a patient and advanced so that itsdistal portion 20 is proximate the surgical site 14. Biocompatiblematerial 12 is then introduced through the first interior lumen 24.Along a portion of the length of the cannula 16, the biocompatiblematerial 12 is in a substantially liquid state with a low viscosity thatfacilitates its delivery through the first interior lumen 24 of cannula16. Prior to being delivered to the surgical site 14, however,cross-linking of the biocompatible material 12 is initiated while thebiocompatible material 12 is within the cannula 16. Initiatingcross-linking of the biocompatible material 12 initiates curing andtherefore increases the viscosity of the biocompatible material 12 priorto its delivery to the surgical site 14. With the viscosity increased,biocompatible material 12 does not flow as readily and the biocompatiblematerial 12 is retained or confined in the desired target area of thesurgical site 14. Therefore, the leakage of the biocompatible material12 into or onto the surrounding tissue at the surgical site 14 isreduced or prevented.

Initiation of cross-linking to cause curing may occur in several waysincluding thermal, chemical, and photo initiation. By way of example,the embodiment shown and described in FIG. 1 utilizes thermal initiationby heating at least a portion of the cannula 16. In this embodiment,control of the curing process may be achieved by monitoring thetemperature of the biocompatible material 12 using temperature element34 and varying the heating of heating element 30 based on thetemperature of the biocompatible material 12. Alternately, and as shownand described in FIGS. 2 and 3, photo initiation may be used to initiatecross-linking of the biocompatible material 12. As shown in FIG. 2,light may be transmitted through at least a portion 58 of the outer wall22 and into the first interior lumen 24 to photo initiate cross-linkingof the biocompatible material 12 therein. Moreover, as shown in FIG. 3,light may be transmitted through a second interior lumen 78 in thecannula 16 and this light transmitted into the first interior lumen 24to photo initiate the biocompatible material 12 therein. In theseembodiments, the curing process of the biocompatible material 12 may becontrolled by controlling the amount of light transmitted to the firstinterior lumen 24. For example, in the embodiment shown in FIG. 2, theintensity of the light source 52 may be controlled by controller 60.Additionally, in the embodiment shown in FIG. 3, the blocking element 86may be moved between first and second positions by controller 88 tocontrol the amount of light transmitted from the second interior lumen78 to the first interior lumen 24. By controlling the amount of heating(thermal initiation) and the amount of light (photo initiation) thatpasses into the biocompatible material, the viscosity of thebiocompatible material at the end of the cannula may have a desiredrange sufficient to reduce or eliminate leakage of the biocompatiblematerial into or onto the tissue surrounding the surgical site.

While the present invention has been illustrated by a description ofvarious preferred embodiments and while these embodiments have beendescribed in some detail, it is not the intention of the inventors torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The various features of the invention may beused alone or in numerous combinations depending on the needs andpreferences of the user.

What is claimed is:

1-25. (canceled)
 26. A device, comprising: an elongate cannula having aproximal portion adapted to be located outside a body, a distal portionadapted to be located within the body adjacent a site to which a curablebiocompatible material is to be delivered, and a first interior lumendisposed between the proximal and distal portions for delivery of abiocompatible material; and an initiation member for initiatingcross-linking of the biocompatible material within the cannula.
 27. Thedevice of claim 26, wherein the initiation member comprises a heatingelement coupled to the cannula.
 28. The device of claim 27, wherein theheating element thermally initiates cross-linking of the biocompatiblematerial.
 29. The device of claim 26, further comprising: a temperatureelement coupled to the cannula.
 30. The device of claim 29, wherein thetemperature element measures a temperature indicative of the temperatureof the biocompatible material.
 31. The device of claim 30, wherein thetemperature element is a thermocouple.
 32. The device of claim 29,wherein the temperature element is located adjacent the distal portionof the cannula.
 33. The device of claim 27, further comprising acontroller operatively coupled to the heating element.
 34. The device ofclaim 29, further comprising: a controller operatively coupled to thetemperature element.
 35. The device of claim 26, further comprising: acontroller operatively coupled to a heating element and a temperatureelement and adapted to control the heating element in response to thetemperature sensed by the temperature element.
 36. The device of claim27, further comprising: an insulating layer on an outer surface of thecannula.
 37. The device of claim 26, wherein at least a portion of thecannula provides for visualization of the biocompatible material throughan outer wall of the cannula.
 38. The device of claim 26, wherein theinitiation member comprises a light source.
 39. The device of claim 38,wherein the light source is capable of photo initiating cross-linking ofthe biocompatible material.
 40. The device of claim 38, wherein thelight source is external to the cannula.
 41. The device of claim 40,wherein at least a portion of the cannula is formed of a materialcapable of transmitting light therethrough for photo initiatingcross-linking of the biocompatible material.
 42. The device of claim 38,further comprising: a controller operatively coupled to the lightsource.
 43. The device of claim 26, further comprising a reservoiroperatively coupled to the first lumen to supply a biocompatiblematerial.
 44. The device of claim 43, further comprising a controlleroperatively coupled to the reservoir to control the supply of thebiocompatible material.
 45. The device of claim 26, further comprising acontroller operatively coupled to a reservoir to control the supply ofthe biocompatible material and a light source to cross-link thebiocompatible material.